Revert "Use windows-2019 image for CI build"
Revert "Use windows-2019 image for CI build"

This reverts commit 9f96880893a45c17d9a7d39c95f12d7ae7583ade.

valadas/Dnn.Platform,nvisionative/Dnn.Platform,valadas/Dnn.Platform,mitchelsellers/Dnn.Platform,mitchelsellers/Dnn.Platform,nvisionative/Dnn.Platform,dnnsoftware/Dnn.Platform,mitchelsellers/Dnn.Platform,valadas/Dnn.Platform,nvisionative/Dnn.Platform,dnnsoftware/Dnn.Platform,dnnsoftware/Dnn.Platform,dnnsoftware/Dnn.Platform,valadas/Dnn.Platform,mitchelsellers/Dnn.Platform,dnnsoftware/Dnn.Platform,mitchelsellers/Dnn.Platform,valadas/Dnn.Platform